Page end signaling means for typewriters, billing machines, and the like



May 2. 1950 F. s. HASSELL, JR 2,505,759

PAGE END SIGNALING MEANS FOR TYPEWRITERS, BILLING MACHINES, AND THE LIKE Filed July 26, 1946 2 Sheets-Sheet l TTORNEYS.

May 2, 1950 F. s. HAssELI., JR 2,505,769

PAGE END sIGNALING MEANS FOR TYPEwRITERs, BILLING MACHINES, AND THE LIKE Filed July 26h 1946 2 Sheets-Sheet 2 INVENTOR BY mp3/L, @www AT TO RN E YS.

Patented May 2, 1950 PAGE END SIGNALING MEANS FOR TYPE- WRITERS, BILLING MACHINES, AND THE LIKE Frank S. Hassell, Jr., Washington, D. C.

Application July 26, 1946, Serial No. 686,419

23 Claims. (Cl. 197-189) This invention relates to typewriters, billing machines and the like, and particularly to novel and improved means and method for page end signaling in the operation of such machines.

One object of the invention is to provide a device for such a machine which can be quickly and easily set to give an audible signal just before reaching a predetermined point on the page being typed.

Another object of the invention is to provide a simple device which can be attached easily to any make conventional type standard or portable typewriter, billing machine or other similar machine without the necessity of using tools, and without either alteringthe said device or altering any part of the machine.

Another object of the invention is to provide such a device which Will visibly indicate to the typist at any time while typing the page exactly how many lines remain either before she reaches a predetermined point on the page or before she reaches the last writing line on the page.

A further object is'to provide a bell signaling device which does not require the conventional type clapper or hammer to strike same, but a device permitting the use of a metal ball, ball retainer and gong and using the force of gravity in combination with the foregoing to t special needs such as the invention outlined herein and to simplify and reduce the number of working parts comprising the bell.

An additional object of the invention is to provide a device that will accomplish the foregoing which is durable, very simple With few Working parts and inexpensive to manufacture.`

Another object of the invention is to provide a device with all the above features which will be constructed and attached so that it will not interfere with the normal operation of the typewriter.

With these and such other objects in viewas will appear hereinafter, this invention comprises the construction, combination and arrangements of parts hereinafter described with reference to the accompanying diagrammatic drawings exemplifying embodiments thereof and forming a part of the invention.

For `a better understanding of the invention reference may be had to the accompanying drawings wherein- Fig. l is a perspective View of one embodiment of the invention;

Fig. 2 is a perspective View of a letterhead and a guide which the typist may use if desired with the means shown in Fig. 1 u

Fig. 3 is a longitudinal sectional view of the means shown in Fig. 1`; i i

Fig. 4 is a sectional view along the line 4 of Fig. 3;

Fig. 5 is a sectional view along the line 5-5 of Fig. 3;

Fig. 6 is a sectional view along the line 6 of Fig. 3;

of Fig. 6;

Fig. 8 is an exploded view of the parts form-V ing the above embodiment of the invention;

Fig. 9 is a view of the above embodiment em-` bodying an adapter for a different sized head or typewriter knob;

Fig. 10 is a perspective view of the adapter;

Fig..11 is an elevational View, partly in section, of anothermodication of the invention;

Fig. 12 is a front View thereof;

Fig. 13 is a sectional view, somewhat enlarged, along the line l3-I3 of Fig. 11;

Fig. 14 is a sectional view, somewhat enlarged, along the line lt-Hl of Fig. 12;

Fig. 15 illustrates another embodiment of the invention;

Fig. 16 illustrates a further embodiment of the invention; and

Figs. 17 and 17A illustrate a further embodiment of the invention. i

Referring to the drawings, I have illustrated my invention as applied to a typewriter, a billing machine or the like, indicated generally by the numeral l and embodying a conventional platen 2, the latter being mounted on a conventional shaft 3 for rotation step by step properly to space' the lines as the typing proceeds. The shaft 3 carries at its end a conventional hand `knob or head li which may be gripped by the typist to rotate the platen 2 and adjust the paper sheets in the machine for the beginning of the typing operation.

In the conventional machine no means are provided Vfor signaling or giving any indication to the typist of the approach to the end of the page `or of the approach to that part oflthe page where it is desired `to discontinue the typing. My invention resides in the embodiment illustrated in Figs. 1-8 inclusive in a meansV indicated generally by the numeral 5, which signals audi- Fig. 7 is a sectional view along the line I-'I is being typed, the device indicates to the typist the number of lines remaining before she reaches either a line previously determined or the end of the page. Moreover, the means 5 is readily attachable to and detachable from the machine with the greatest facility and in the particular embodiment shown the mea-ns 5 is mounted upon the knob or head 4 of the platen 2 in an easily attachable and detachable manner whereby within a few seconds the device may be attached by hand without the aid of any tool to any model or make of conventional standard or portable typewriters, billing machines :and similar ma- Y chines without any alteration whatever of the machine. This means may be with equal facility detached from the machine or, as 'will hereinafter appear, the signaling and indicating means may be rendered inoperative or operative at any time by the typist.

More specifically, the invention comprises a compact unit 5 which is carried by the knob or head 4 of the platen, the whole attachment being so small as to form only a short extension of the shaft 3 lbeyond the knob 4. It comprises essentially three parts, namely, an attaching means I for attachment to the knob 4, a gong or similar device II, and an indicator I2 which, during the typing operation, rotates with the platen 2, attaching means I0, and the gong II, and which may be manually swiveled or rotated independently of the platen 2 to make the desired adjustment for signaling to the typist when that part of the page isV reached during the typing operation.

The gong II is cup-shaped and the cylindrical indicator I2 projects into this cup-shaped gong. The indicator I2 in the embodiment shown is of cylindrical shape and is made of transparent mae teral as, for example, and preferably, of a plastic material of a character to have the desired strength and resistance to breakage. It is provided on its interior surface with a spiral track I3 for accommodating a ball indicator I4 whereby, as the platen and the means 5 are rotated in steps according to the line spacing, this ball indi- 7 cator I4 is caused by gravity to traverse the spiral track I3. The cylinder I2 is mounted on a shaft I5 which passes longitudinally therethrough. The spiral track I3 is provided with side walls I3 of suicient height or depth to prevent accidental displacement of the indicator ball i4 axially from one turn of the spiral track to the other. That is, the height of the track walls I3 cooperatively with the shaft I5 prevent such accidental dis placement and accordingly the only movement of the ball indicator I4 is along the spiral track I3, either inwardly toward the gong II during the typing operation or outwardly therefrom during adjustment of the metal ball I4 to the desired position along the cylinder I2.

A scale is provided along the track I3 of the cylinder, the distance between the divisions of the scale corresponding to the distance the cylinder I2 moves in the direction of the spiral when the platen 2 is rotated a distance equal to the spacing of a line. This scale should comprise divisions in any number desired and visibly in the drawings are divisions from zero up to '75. This scale begins near the inner end of the cylinder I2 and follows the track I3 Voutwardly clockwise, looking towards the outer end of the cylinder. In the 4particular embodiment shown, this scale is incorporated on the outside of the cylinder and, as will be more particularly described hereinafter. the cylinder I2 is swiveled by hand on the shaft 4 I5 independently of the platen 2 to adjust the metal ball I4 to that part of the scale on the track corresponding to that point on the page where the signal is to be given.

The signal is given when the metal ball I4 reaches a predetermined point in the spiral track I3 and, in the particular embodiment shown, this point in the track I3 is an outlet I6 passing radially outward from the track I3 through the shell of the cylinder and in this embodiment this outlet IB is disposed at a point having an arcuate distance from the zero mark of the scale which is equal to about a quarter of one complete revolution of the cylinder I2 about the axis determined by the shaft I5. There is mounted to rotate with the cylinder I2 a guide and retainer I'I, this retainer being in the form of a short tube disposed in alinement with the outlet I6 in the cylinder and being adapted to guide the metal ball I4 as it drops by gravity through the outlet I6 to fall upon the gong I I at that point in the typewritten page where the signal is to be'given.

The setting of the means 5 for indicating the progress during the typing of the page and giving the signal at the end of the page is very simply effected as follows.

With the typing page or paper inserted in the machine so that the top portion of it can just be seen, the typist grips the cylinder I2 with the hand and turns it independently of the platen 2 counterclockwise looking inwardly toward the gong, until the indicator ball I4 appears just below the number on the scale on the cylinder track at which the typist wishes to be signaled. That is, the cylinder is rotated counterclockwise for adjustment, assuming that the metal ball I4 is disposed between the scale numberand the inner end of the cylinder or disposed at the inner end of the cylinder. If the ball should happen to be located at a scale number higher than a particular number at which the signal is to be given, naturally the rotation of the cylinder I2 would be clockwise to bring the ball to the desired number. This number corresponds to that part of the page at which or near which the typing is to be discontinued as measured against the scale by a ruler 20 or already known by the typist. This number on the cylinder can easily be observed between the ball and the shaft I2 at the typists normal sitting position. She then proceeds to type the page and as she `proceeds the cylinder I2 rotates with the platen 2 and accordingly the indicator ball i4 travels inwardly along the track I3 inwardly of the cylinder. At any time while the page or paper being written on is in the machine the typist can by glancing at the cylinder and the scale number centered between the ball and the shaft l5 observe the number of lines yet remaining on the sheet or page to be typed. The ball moves horizontally inwardly along the casing of the cylinder and within the spiral groove I3 from right to left as the platen is turned during operation of typing. When the ball reaches the outlet I6 it drops by gravity as indicated above through the guide and retainer II to give the signal, and in the particular embodiment shown this signal is given by the ball striking the inner surface of the gong I I. It is understood that the metal ball I4 'can move freely relatively to the spiral track I3 so as to always assume a position at the bottom of the cylinder I2 and also that the guide or retainer II and the outlet I6 are of larger diameter than the ball I4 so as to facilitate the passage of the indicator ball I4 therethrough in both directions. In the particular embodiment shown the guide I1 is of a diameter corresponding to the width of the track I3, which is slightly larger than the diameter of the metal ball I4.

In the particular embodiment shown the inner end of the spiral track I3 is provided at a point adjacent the outlet I 6 with a ridge I8 which is high enough to retard the falling of the metal ball I4 through the outlet I6 for a turn of two or three scale numbers on the cylinder but not high enough to prevent the ball from tumbling over this ridge by gravity after an arcuate movement of the cylinder through two or three scale numbers. That is, the ball I4 is retarded by this ridge I8 for only a short arcuate distance indicated, whereupon it tumbles over into the outlet I6 and without hindrance from the shaft I5, since the distance between thte ridge I8 and the shaft is larger than the diameter of the ball. This contributes towards accuracy in signaling.

From one to four scale lines as may be desired before rea-ching the predetermined point on the page at which the signal is to be given, the met-al ball I4 plunges over the ridge I 8 through the hole or outlet I6 to deliver the signal, and in the particular embodiment shown as indicated the signal is delivered by the impact of the ball against the gong II or the normal vibration of the means 5 while the typist continues to type subsequent to the initial plunge of ball I4 onto the gong II will ordinarily produce a signal of sufficient loudness. The ball as indicated is retained in the retainer I'I. When the typist receives this signal she glances at the scale number on the cylinder just below the shaft I5 at the extreme lefthand of the spiral track I3. If, for example, the scale number is zero, she knows she has reached the end of that part of the page where the typing is to be discontinued. If the scale number is one, two, three or four, then she knows she lacks one, two, three or four scale lines, respectively, before reaching the predetermined stopping point on the page being typed. This variance of from one to four scale points is sometimes caused by the movement of the typewriter or other machine while in operation. For example, the operator who throws her carriage back with great force will usually have about three more lines to write after being signaled than the typist who moves the carriage back with less force. However, after becoming familiar with the device, which familiarity can be obtained with very little experience, the typist may make proper allowance for the extra lines in setting so that it will ring on the last line rather than one, two, three or four lines in advance.

However, being signaled a line or so in advance is no hindrance to the typist but on the contrary is advantageous because then she will be signaled before she inadvertently starts the rst line of a paragraph on the last line of a page. Also, by glancing at the scale numbers on the cylinder, she can tell in a second exactly the number of lines remaining. After the first signal the ball continues to make a little noise on the gong, which constantly reminds the typist that she is near the bottom margin. i

When for any reason the operation of the signal and indicating means is not desired as, for example, when the typist has one or more onepage letters to vwrite or one or more short bills to write, she can render the signaling means inoperative. This is effected by a means I9 which is in the form of a curved plate or gate disposed on the outside of the cylinder I2 and adapted to occupy either a position between the outlet I6 and the retainer I1, thereby closing the outlet I6 and keepingthe ball within the cylinder and preventing any further signaling, or to a position (that shown in full lines) where this gate is moved to a position to one side where it does not obstruct the passage of the ball I4 into the retainer I1. The means for supporting and actuating this gate I9 will be more particularly set forth hereinafter.

The scale of the ruler 2U of Fig. 2 corresponds to the scale on the track I3 of the cylinder I2 and by placing the ruler or tape 25 up against the sheet to be typed the typist can determine at a glance where the indicator ball I4 is to be set just before beginning the typing operation.

In the particular embodiment shown the cylin-I der I2 is provided with a back stop 2I immediately behind the outlet I 6 which extends up high enough to prevent the metallic ball I4 from accidentally passing between the back stop 2| and the shaft I5. Also the outer end of the cylinder or the outer end of the spiral track I3 is provided with a stop means 22 for blocking thel outward travel of the ball and preventing it becoming wedged or caught in any way at the outer end.

The device comprising the three parts I0, I I and I2 is mounted on the machine for ready attachment and detachment without disturbing or altering the machine in any way. This is effected by the retaining means IIl which is in the form of a cup-shaped gripping and holding member and is formed of a slightly flexible and resilient material as, for example, of rubber, natural or synthetic, and the means 5 is readily attached to the machine by slipping the cup means I0 over the platen knob 4. This means IIJ rmly frictionally grips the knob 4 and accordingly means Il) rotates with the platen 2. This means lll is provided with a roughened or corrugated surface 25 which enables the typist to rotate and adjust the platen 2 by hand at any time desired. The device 5 may be detached from the machine by simply slipping the cup-shaped member It off of the platen knob 4. This can be effected as above described very quickly and without disturbing or `without the necessity for alteration of the machine.

The mounting of the parts I0, III and I2 of the device as a unit may be effected in any suitable manner. In the particular embodiment shown the three parts are assembled together as a unit by a means comprising a shaft `I5 which has an enlarged inner end I5', a screw 25 which is screw-threadedly attached to the end of the enlarged section I 5 of the shaft, and a disc holding member 21. The latter is disposed within the cup-shaped holding member l0 and lies flat against the bottom of this member. In the parn ticular embodiment shown it is of, roughly, the same diameter as the platen knob 4. It is provided with a counter sunk hole in the center to receive the head of the screw 26 when the latter is screwed into the shaft section I5'. The outer end of the cylinder I2 is provided with a central countersunk recess for the reception of a correspondingly shaped screw head of the shaft I5. The enlarged section I5 of the shaft is provided inter-mediate its ends with a recess or opening 28 for the reception of a holding pin 29 which fastens a holding disc 3U to the enlarged section I5' of the shaft. This disc 30 is provided with a recess or opening 3l adapted to receive the fastening pin 29, the opening 3l passing radially through the holding disc 3|] and registering with the recess 28 formed in the shaft section I 5'. The gong! ll is disposed against the holding disc 3i) on one side and against a pair of spacing discs 32 and 33 on the other side, these discs 33, 32 and 33 having openings through the centers thereof accommodating the enlarged section l of the shaft. Another disc Lil is provided with an opening in the center for the 'accommodation'of the shaft section i5 and is clamped tightly against the outer disc 33. by the screw 23 and the disc 2l. In the particular embodiment shown, the disc is clamped Yagainst the outside of the holding member iii, the iatter having a central opening at the bottom which is smaller than the disc 34 but it is understood that the disc 34 may be of small enough diameter to fit within the opening formed in the bottom of the holding member I3 with its outer surface clamped tightly against the disc 2l', since the spacing discs 32 and 33 are' sufficient to avoid the rubber-like holding member iii coming in contact with and deadening the gong ll.

In the particular embodiment shown the retaining and guiding means il is carried by a disc 35 which is also provided with an opening for threading the same over the shaft section i5' and this disc is provided with a lug 33 extending toward the inner end of the cylinder yi2 and enn gaging a holding recess 3i formed in the end surface thereof. By this means the retaining and guiding means Il is caused to rotate with the cylinder i2, the two being thereby locked together.

In the particular embodiment shown the 'gate I9 is carried by a disc 38, the later being disposed between the disc 35 and the inner end of the cylinder l2. This disc 33 has a sectionil removed from the periphery thereof 'for the purpose of clearing the holding lug 36 of the discY 35 and for the purpose of providing limited rotary movement of the disc 38 with respect to the cyl-k inder l2 and the disc 35 to enable the gate i3 to be operated to either of its two positions of operation. The side walls iB of the recess or removed section 39 form stops for engaging the lug 35 in the two operative positions of the gate I9 so that when one of the walls lli is in engagen ment with the lug S3 the gate is in the open position and when the other side wall is in engagen ment with the lug 35 the gate i3 is closed. In the l particular embodiment shown the disc 33 and the gate i9 are integrally formed, the gate i@ being carried b a lug I9 extending axially from the periphery of the disc 38. A finger operating piece il is turned up radially and outwardly of the periphery of the disc 38 from the lug i3' to form ready means for moving the gate I9 to either of its operative positions. i

The cylinderV l2 is journaled or swiveled on the shaft i5, I5' for movements independently of the holding member l@ and the shaft. It is swiveled at its outer end on the screw head of the shaft section l5 and it is swiveled at the inner end by being provided with a central opening ac- Y commodating in a swiveling manner the enlarged section l5 of the shaft. There is disposed between the disc 3i! and the disc 35 a leafY spring member d3, the latter engaging on its convex side the disc 3s and engaging on its concave side at outer ends thereof the disc 35. By this means the disc 35 and disc 33 are held in assembled relation with respect to the cylinder i2 and the cylinder together with the discs 35 and 38 may be rotated about the shaft and against the friction entailed'by the pressing ofthe leaf spring 43 against the inner end thereof. Inorder to preventthe ac-` 8: cidental movement of Vthe `disc 38 and 'the gate i9 from one position to the other, the disc 38 may be provided with. friction lugs or bosses on the surface thereof adjacent the end of the cylinder A l2, these lugs frictionally engaging the end of the cylinder to militate against such accidental movement either when the cylinder I2 is rotated independently of the platen 2 or when the latter isrrotated during the operation of the machine. Two similar friction'lugs or bosses 46 are provided on the surface of the disc 35 for engaging the disc 35 and thereby tending to brake the movement of the disc 38.

When the platen knob 3 is of a dimension differl ent from the interior diameter of the holding member li! as, for example, when the diameter of the knob 4 is smaller than the interior diameter of the holding member li it is desirable to provide an adapter to adapt the device 5 to this particular machine knob. In Figs. 9 and 10 is shown such an adapter. This adapter is indicated at 50. This adapter 3i) may be made of any suitable material and preferably of a flexible and resilient material as of rubber, synthetic or natural. This adapter has an exterior diameter equal to or slightly less than the internal diameter of the holding member and, like the holding member I0 which has a holding flange i0', is provided with a holding flange for engaging the side of the platen 'knob to hold the device 5 firmly on the knob.

In the embodiment of 1l to lli the spiral track member i2 comprises a spiral track structure 53 the turns of which, instead of being arranged sereni -like are formed coplanar about fthe' axisl of the shaft 3.

The member if. and its track are Somewhat diagrammaticaliy illustrated. The inner end of the track which is disposed adjacent an assembly shaft 1 is closed, while the other end of the track which is disposed at the peripheral surface of the member i2", is open as indicated at 53. The'turns of the track 63 or the chamber track 53' thereof therefore spirals about the shaft 3l from the inner end 64 outwardly and radially in turns which gradually increase in diameter. A scale similar to thatY on the indicator member i2 of Fig. l is applied to the front Vsurface 32 of the indicator The zero mark of this scale is indicated at the outer end of the track at E3 and in the particular embodiment shown this scale runs up to eighty divisions. The metallic ball indicator i4 traverses this track when the indicator spiral track member l2 is rotated and the member l2 may be adjusted at the beginning of the typing of the page to give the signal at any point in the pagev desired for arresting the typing operation. lFor the purpose of adjustment, the indicator member l2 may be swiveled by hand as by engaging the knob 88 on the'front surface and rotating the member to bring the ball weight indicator I4 to the desired scale number or di-A vision on the scale indicated in Fig. l2, similarly7 as described with respect to the embodiment of Figs. 1 to 8. As the typist types the page the rotation of the platen 2 and the shaft l rotates the member I2' through the friction drive formed in part by the spring member 43 engaging the disc disposed about the shaft 3l' and at the inner surface of the gong Il. There is some friction also between the bolt head on the shaft 3l and the front disc side of the member i2', this frictional clutching means enabling the rotation of the member I2 independently or the shaft 3 to adjust the position of the ball indicator I4 in "the spiraltrack. Asthe typist progresses with to be continued. Finally, the ball indicator i4 rolls out of the open end 55 of the track on to Athe inner surface of the gong II, either to deliver a sound signal to the typist when the ball iirst falls upon the gong, or the continued typing `voperation causes a sound to be produced by the ball I4 vibrating or being jostled upon the gong. For facilitating the reentry of the track through the open end 66 by the ball I4, the outer end wall of the track is turned outwardly as indicated at 65 towards the gong II to form the guide or scoop for assuring the reentry of the track upon the member I2 being rotated counterclockwise. A stop l is provided about a third of a revolution from the open end of the track to prevent the ball member from becoming lodged or wedged between the wall of the track and the inner surface of the gong I I'.

The ball element I4 and its signal function may be discontinued at the will of the typist. This is effected by means of a screw element 69 which is screw-threadedly attached to an opening in the front disc 62 of the member I2', this screw-threaded opening being in line with the outer portion of the track chamber 53' just in advance of the opening [it as illustrated in Figs. 12 and 14. This screw projects into the chambei' at this point far enough to block the eXit of the ball indicator I4 through the opening 66 and by engaging the knurled head of the screw 69 the typist may withdraw the screw until the inner end clears the path of the ball indicator I4.

The means III for holding the indicator in a .readily attachable and detachable manner may be similar to that of the embodiment of Figs. 1 to 8. Spacing means 65 are provided between .fthe gong II and the member I sufilcient to ,cause the latter to clear the gong II and thereby ,avoid deadening of the sound of the gong. The ,shaft 6l may be generally similar to the shaft I5 ,of the embodiment of Figs. 1 to 8 but it is understood that the mounting of the indicator mem- :loer I2 and the gong II is purposely shown diagrammatically since any suitable mounting of V,the elements Ill, II and I2 may` be provided. i lThis embodiment has the advantages of being more compact and of being less susceptible to vibrations and shocks during the typing operation and therefore more accurate in indication and signaling means.

It is understood that the indicating means I2 and I2 of the invention may be used with any other form of signaling than that shown in the drawings. For example, the gravity indicator member I4 may be utilized to operate a visual signal or a sound signal of any other character than that indicated. For instance, the gravity indicator member I4 may be utilized to close an electric circuit when it passes out of the open end of the track, which circuit controls a suitable ndicator or sound signal through electrical means.

Fig. 15 illustrates a modification of the structure of the indicator member I2 of Figs. 11 to 14. In this embodiment the spiral track is formed by a pair of disc members 'I5 and 'I6 which are provided with complementary spiral tracks on their opposing sides for the accommodation of the ball indicator I4. The complementary spiral track l0 on the inner surface of the disk 'I5 is shown at 'I'I and the corresponding complementary spiral track on the disk I6 is shown at 18. The two discs are mounted on a shaft "I9, which shaft may be similar to the shaft 61. In the particular embodiment shown these discs are spaced from each other by a sleeve and in this embodiment this sleeve 80 is formed in two halves, one half being integral with the disk I5 and the other half being integral with the disc i6. The disc I5 is provided with a hub 68 similar generally to the hub S8 of Fig. 14, and this hub 68' is preferably knurled to providea friction grip for the fingers inrotating the indicator unit I4 for adjustment at the beginning of the typing of a page. Each of the complementary spiral tracks 'Il and 'I8 is provided with a closed end adjacent the hub which together form the stop at the inner end of the track for the ball, this stop corresponding to the stop 64 of Figs. 12 and 13. At the outer end or in advance of the outer end of the spiral track, which end is disposed at the periphery of the discs 'I5 and 16, are disposed complementary guides 8| and 82 which project slightly beyond the peripherics of the discs and towards the gong II' for the purpose of guiding the ball backinto the groove from its position on the gong. These complementary guides or scoops may be formed integrally with the discs 'I5 and 16, which are made of transparent material as, for example, a transparent plastic. These guides 3l and `82 not only extend in a direction toward the gong II but also in the direction of the spiral track at its outer end so as to facilitate the guiding of the ball indicatorinto the track as the indicator member I4 is rotated by the fingers.

This embodiment of Fig. 15 has `the advantage over the embodiment of Figs. 11 to 14 in that a larger and heavier indicator ball I4 may be used on an indicator member of the same diameter and same number of spiral track turns.

In the embodiment of Figs. 1 to 8 I have illustrated the spiral track indicator member I2 somewhat diagrammatically for the purpose of illustrating the purpose of the principle of the invention. In Fig. 16 I have illustrated this indicator member as being formed of a transparent cylinder as, for example, being made of a transparent plastic material. The spiral track is formed by a separate spirally constructed member 86, which member is assembled on the inside of the cylinder 85 after the latter is formed. This cylinder 85 may be formed with one end closed. The spiral track member 86 may then be inserted lengthwise in the cylinder and thereupon the end disc 85' may be assembled and fastened to the end of the cylinder 85, this end disc 85' preferably being, but not necessarily so, of the same material of which the cylinder 85 is formed. In the particular embodiment shown, the spiral member 8E which, together with the inner surface of the cylinder 85, forms the spiral track, is formed of wire of suitable material and dimensions. The outer end of the spiral member Sii is provided with a bent end 22 which corresponds to the stop 22 of Fig. 3 for preventing wedging of the ball indicator I4 at the outer end of the track. rIhis structure of Fig. 16 has advantages from the standpoint of quantity production.

`In Fig. 17 I have illustrated a modified means for readily attaching and detaching the indicator to most any make of typing `maohineon-the market. This modied holding means comprises a flexible holding member SI1, which is similar` to the iiexible holding members III described above.

l Instead, however, of the disc 21 of Figs. 1 to 8 which'is clamped to the shaft l5, I have here illustrated a winged disc-like member 9|, the inner part 9,2 of this winged member being in the form of a disc which is clamped tightly against the spacing meansas, for example, the discs 32, 33 and 34 of Figs. 1 to 8, or otherwise anchored to the shaft I5, El or 19. The outer part of this member 9| is formed of a multiplicity of blades 93, in the particular embodiment shown there being four, which are formed integrally with the inner part 92 and are preferably equally and uniformly spaced thereabout. These wings or blades 93 extend outwardly from the part 92 in both a composite radial and axial direction, that is, these wings 93 lare from the inner part 92 towards the typing machine. The outer ends of these wings or blades 93 thus form gripping parts for engaging the outer end surface of the knob or head 4. On certain makes of typing machines these knobs are as shown in Fig. 3, in other types the knob is formed with an outer central boss-like part of larger dimensions than that indicated in the head or knob 4 of Fig. 3, and the structure of the member 9i readily accommodates itself to the different types of knobs on the different makes of typing machines on lthe market. In Fig. 17 I have shown in dotted lines a modied knob or head il which has a central boss-like portion 94 of larger length or depth than that indicated on the corresponding knob or head 4 of Fig. 3.

What I claim is:

l. An attachment for a typing machine having a rotative platen, comprising fastening means which is readily attachable to and detachable from the platen, a member rotatable with and independently of said fastening means and having a spiral track adapted to accommodate an indicating member, an indicating member disposed in and Wholly supported by said spiral track and means operated by said indicating member to indicate when the indicating member reaches a predetermined point in said spiral track.

2. An attachment for a typing machine having a rotative platen, comprising attaching means Yfor ready attachment to and detachment from `the platen, a cup-shaped gong, an indicator member rotatable both with and independently of said platen, said member having a spiral track disposed about the axis of the platen, a metallic ball traversing said spiral track during the rotation of the platen, and said gong being positioned to be engaged by the ball when it reaches one end of the spiral track.

v3. An attachment for a typing machine having a rotative platen, comprising attaching means Afor ready attachment to and detachment from the platen, a cup-shaped gong, a hollow indicator member rotatable both with and independently of said platen, said member having a spiral track disposed therewithin and disposed about the axis of the platen, a metallic ball traversing said spiral track during the rotation of the platen, and said gong being positioned to be engaged by the ball when it reaches one end of the spiral track, said indicator' member having a scale which follows the spiral track and being of transparent material whereby the ball is exteriorly visible in the track.

4. An indicating means for the platen ,of a typing machine comprising a hollow member rotatable -with the platen of the typing machine and having therewithin a spiral track adapted to be traversed by an indicator disposed therein, an indicator in said track, and said member being of transparent material whereby the indicator is exteriorly visible.

5. An indicating means for the platen oa typing machine comprising a member rotatable with the platen of the typing machine and having a spiral track adapted to be traversed by an indieating member, an indicating member disposed in said track and following the same by gravity acting on the indicating member as the member is rotated and signal means operated by said indicating member when it reaches a certain point in the spiral track.

6. An indicating means for the platen of a typing machine comprising a member rotatable With the platen of the typing machine and having a spiral track adapted to be traversed bya ball indcator disposed therein, a ball in said track, `a gong, and said gong being positioned to be engaged by the ball when it reaches one end oi the spiral track.

'7. An indicator means for a typing machine having a platen comprising a support rotatable with the platen, a transparent indicator member rotatable with the platen and support, said transparent member having a spiral track in the in- Y terior thereof adapted to accommodate a cooperating indicating member, an indicating member in said track, said cooperating indicator member following said spiral track by gravity as the platen rotates, and an indicating scale on said member adjacent said spiral track.

8. An indicator means for a typing machine having a platen comprising a support rotatable with the platen, a transparent indicator member rotatable with the platen and support, said transparent member having a spiral track in the Vinterior thereof adapted to accommodate a cooperating indicating member, an indicating member in said track, said cooperating indicator member following said spiral track by gravity as the platen rotates, an indicating scale on said member adjacent said spiral track, and means giving an indicating signal when the cooperating indicating member reaches one end of said spiral track.

9. In an indicator attachment for the platen of typing machines, the combination of means for fastening the attachment to rotate with the platen, a member rotatable with the platen and comprising a spiral track adapted to accommodate a metallic ball traversing said spiral by gravity as the platen rotates, a metallic ball in said track, said spiral track having an open end, and a gong having a signal part disposed below the open end of said spiral track whereby said ball drops upon said signal part when lit reaches-the open end of the spiral track.

l0. In an indicator attachment for the platen of typing machines, the combination of means for fastening the attachment to rotate with the platen, a member rotatable with the platen and comprising a spiral track adapted to accommodate a metallic ball traversing said spiral by grav.- ity as the platen rotates, a metallic ball vin' said track, said spiral track having on `open end, a gong having a signal part disposed below the open end of said spiral track whereby said ball drops upon said r gong part when it reaches thelopen end of the spiral track, said member being of elongated form with the spiral trackldisposed about the axis thereof and progressing axially therealong with the inner end of the spiral 'being theopen end.

1,1. In an indicator attachment for the platen 0f typing machines, the combination of means for fastening the attachment to rotate with the platen, a member rotatable with the platen and comprising a spiral track adapted to accommodate a metallic ball traversing said spiral by gravity as the platen rotates, a metallic ball in said track, said spiral track having an open end, a gong having a signal part disposed below the open end of said spiral track whereby said ball drops upon said gong part when it reaches the open end of the spiral track, said member being of elongated form with the spiral disposed about the axis thereof and progressing axially therealong, with the inner end of the spiral being the open end, and a ball retaining tube disposed at the open end of the spiral track and between the open end and that part of the gong which is engaged by the ball.

12. In an indicator attachment for the platen of typing machines, the combination of means for fastening the attachment to rotate with the platen, a member rotatable with the platen and comprising a spiral track adapted to accommodate a metallic ball traversing said spiral by gravity as the platen rotates, a metallic ball in said track, said spiral track having an open end, a gong having a signal part disposed below the open end of said spiral track whereby said ball drops upon said gong part when it reaches the open end of the spiral, the turns of said spiral being coplanar, with the outer and open end thereof disposed adjacent the periphery of the member.

13. In an indicator attachment for the platen of typing machines, the combination of means for fastening the attachment to rotate with the platen, a member rotatable with the platen and comprising a spiral track adapted to accommodate a metallic ball traversing said spiral by gravity as the platen rotates, a metallic ball in said track, said spiral track having an open end, a gong having a signal part disposed below the open end of said spiral track whereby said ball drops upon said gong part when it reaches the open end of the spiral, the turns of said spiral being coplanar, with the outer and open end thereof disposed adjacent the periphery of the member, and means guiding said ball on to said gong and retaining the same against displacement.

14. An indicator attachment of the character set forth in claim 12 wherein the spiral track is formed by two spaced discs, said discs having complementary spiral grooves forming the spiral track.

15. An indicator attachment of the character set forth in claim wherein the rotatable member comprises a transparent cylindrical casing and a separate spiral coil disposed in the cylinder and forming the track.

16. An indicator attachment of the character set forth in claim 10 wherein the rotatable member is provided with retarding means disposed at the open end of the track.

17. In an indicator attachment for typing machines, a means for readily attaching the attachment to and removing it from conventional typewriter platen knobs, comprising a flexible resilient cap adapted to surround the knob, and a disc-like member disposed in the cup, said disc-like mem- 14 ber having its peripheral parts axially flared from the central portion thereof toward the knob and adapted to engage the knob at points adjacent the periphery thereof.

18. An indicator attachment of the character set forth in claim 17 wherein the disc-like member is provided with a multiplicity of flaring bladelike members forming the periphery thereof and adapted to engage the knob.

19. In combination with an indicator attachment for typing machines, a means for readily fastening the attachment to and removing it from conventional typewriter platen knobs comprising a flexible resilient cup adapted to surround and grip the knob and means for fastening the resilient cup to said attachment, said indicator attachment being rotatable independently of the resilient cup.

20. In combination with an indicator attachment for typing machines, a means for readily fastening the attachment to and removing it from conventional typewriter platen knobs comprising a flexible resilient cup adapted to surround and grip the knob and mea-ns for fastening the resilient cup to said attachment, said last-named means comprising a disc-like member disposed on the bottom of the cup, the bottom of said cup being provided with an opening for the accommodation of a shaft.

21. An indicating means for the platen of a typing machine comprising a member rotatable with the platen of the typing machine and having a spiral track adapted to be traversed by a ball indicator disposed therein, a ball indicator in said track, and a gong positioned to be engaged by the ball indicator when it reaches a predetermined point of the spiral track.

22. An indicating means for the platen of a typing machine of the character set forth in claim 2l wherein the rotatable member comprises a cylinder having a circular formed spiral wire member disposed therein and forming with the inner .surface of the cylinder said spiral track.

23. An indicating means for the platen of a typing machine of the character set forth in claim 21 wherein the rotatable member is a cyliner having a spiral track in the interior thereof, said cylinder having an opening on the underside thereof at said predetermined point for the indicator to drop by gravity upon the gong and means for closing said opening.

FRANK S. HASSELL, Je.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 787,772 Labosh Apr. 18, 1905 983,340 Zumpe Feb. 7, 1911 1,304,458 Dari' May 20, 1919 1,326,346 Hsieh et al Dec. 30, 1919 2,298,742 Larose Oct. 13, 1942 2,366,265 Jensen Jan. 2, 1945 2,404,861 Petschauer July 3D, 1946 

